A boiler used for heating or warm water is a device configured to heat a desired area or supply warm water by heating water or direct water (hereinafter referred to as a “heating medium”) being heated by a heat source, and the boiler includes a burner configured to combust a mixture of a gas and air and a heat exchanger configured to transfer combustion heat of a combustion gas to the heating medium.
Boilers produced early on used a heat exchanger which heats a heating medium using only sensible heat generated when a burner performs a combustion operation, but a condensing boiler, which has a sensible heat exchanger configured to absorb sensible heat of a combustion gas generated in a combustion chamber, and has a latent heat exchanger configured to absorb latent heat generated by condensation of water vapor contained in the combustion gas which underwent heat exchange in the sensible heat exchanger, is lately being used to improve thermal efficiency. Such a condensing boiler is being used in oil boilers as well as gas boilers, thereby contributing to an increase in boiler efficiency and a reduction in fuel cost.
As described above, a conventional condensing type heat exchanger including a sensible heat exchanger and a latent heat exchanger is configured with a structure in which a blower, a fuel supply nozzle, and a burner are installed above a housing, and the sensible heat exchanger and the latent heat exchanger, which each have a heat exchange fin coupled to an outer side of a heat exchange tube, are sequentially installed inside the housing below the burner.
However, in the conventional condensing type heat exchanger, there is a problem in that a volume of the heat exchanger is increased due to the blower being disposed above the housing and the structures of the sensible heat exchanger and the latent heat exchanger which are individually installed inside the housing.
As prior art for improving heat exchange efficiency and minimizing volume while resolving such a problem, Korean Registered Patent No. 10-0813807 discloses a heat exchanger configured with a burner disposed at a central portion of the heat exchanger, and with a heat exchange tube wound around a circumference of the burner in the form of a coil.
The heat exchanger disclosed in the above-described patent has problems in that the tube is deformed into a rounded shape when the tube is formed into a flat shape and a pressure is applied to a heat transfer medium portion, and a thickness of the tube is to be thick since the tube is manufactured by being rolled up.
Further, the conventional heat exchanger is configured with a structure in which a heat exchange tube is wound around a combustion chamber in the form of a coil, and a heating medium flows in only one direction along the heat exchange tube such that there is a disadvantage of a wide heat transfer area being unable to be secured since a heat exchange between a combustion gas and the heating medium is performed only in a local space around the heat exchanger formed in the form of a coil.
As another example of prior art for improving heat exchange efficiency while resolving a problem of a volumetric increase and minimizing volume, Korean Registered Patent No. 10-0406133 discloses a heat exchanger of an upward combustion type condensing gas boiler, which includes a heat exchange tube (a stainless steel corrugated tube) wound around a combustion chamber in the form of a coil, and a heating medium flowing through the heat exchange tube.
The heat exchanger disclosed in the above-described patent has a structure in which a burner is inserted and assembled into a lower portion of a heat exchanger such that there are problems in that the burner is difficult to disassemble and assemble when maintenance such as cleaning of the heat exchanger is required, and a work space for accessing a combustion chamber side of the heat exchanger is difficult to secure.